1. Field of the Invention
The present invention generally relates to a handover in a mobile communication system.
2. Background of the Related Art
Mobile radio communication systems are used in everyday life. Garage door openers, remote controllers for home entertainment equipment, cordless telephones, hand-held walkie-talkies, pagers, and cellular telephones are all examples of mobile radio communication systems. Cellular radio systems provide high quality service that is often comparable to that of landline telephone system.
A cellular radio system may include cell phones and base stations. Cell phones are portable telephones which end users may use to make telephone calls. The base stations communicate with the cell phones using radio signals. Base station may be stationary and have relatively large antennas. As a user with a cell phone travels, the user is most likely moving away or getting closer to the base station with which the cell phone is communicating. As the cell phone is moved away from the base station, the radio signal between the cell phone and the base station becomes weaker. Eventually, the radio signal will become so weak that the cell phone and the base station are not able communicate. When the radio signal becomes too weak for communication to occur, the cell phone starts to communicate with another base station that is closer to the cell phone. The closer base station will provide a stronger signal than the further away base station. This switching of base station is often referred to as a handoff (much like the handing off of a baton by a relay runner in the Olympics).
Unfortunately, a handoff may result in a degraded radio signal between a base station and a cell phone. When such a degraded radio signal occurs, it can be very annoying for the user of the cell phone. For instance, if the user of the cell phone is conducting a telephone conversation when the radio signal is degraded, the sound coming out of the cell phone may include an overwhelming amount of static. Accordingly, there is a long felt need to minimize degraded radio signals that occur as a result of a handoff.